I suspect this is largely due to DDG using Bing under the hood, which has led to similar weirdness in the past, eg all major porn sites disappearing from the results in Singapore (while Google still showed them, mind you!). Still super disappointing though, and yet another reason why trying to build a better search engine on top of someone else's tech is a non-starter.
Maybe that's the real problem. There have been some recent articles on HN about how "search is broken" and maybe this article falls under that. Because what really gets me is that there is plenty of legit content on "pirate sites" and blocking them completely cuts off that content.